This filter adopts dissymmetrieal semipermeable film which is made from macromolecule material with special process.The raw liquid flows underpressure,inside or outside the filim.The macromolecule substance and colloid particles in the raw liquid are clogged at the film surface and are brought away by ciculating raw liquid.Then the raw liquid becomes inspissated,and further more,the subtance in liquid is separated,concentrated.The production capacity:1-100T/h